Parts and pieces of many different types and shapes are made by stampings and progressive stampings for use in a variety of different assemblies and constructions. Metal can be shaped into many different forms and configurations by the application of force causing a metal blank to conform to the shape of a die used while applying the force. Simple parts and pieces can sometimes be made by a single stamping. In a single stamping, force is applied in a single event so that the metal conforms to a die used while applying the force. For more complex parts or parts taking a shape quite different from the original metal blank, progressive stampings are used. In progressive stampings, a series of dies are used in a series of stamping events, with each die and each stamping event forming the metal in stages from the original blank to the desired final formation.
The loads applied to the metal in a stamping process can cause a variety of flaws to form in stamped metal pieces and parts. For example, the metal may not conform as desired to the die used in the stamping process. Further, the force applied can cause cracks and other flaws in the metal. It is necessary to remove defective parts so that the defective parts are not incorporated into a final assembly. While visual inspection can be used for some defects, visual inspection by individuals is slow and not completely reliable if the defects are small.
Stamping is often used to make parts and pieces inexpensively, since a stamping event is a rapid occurrence. Accordingly, parts can be formed quickly and inexpensively, with minimal waste. To ensure a high percentage of quality parts are shipped to customers cost effectively, testing procedures for stamped parts must be performed rapidly and reliably. Preferably, a testing method occurs as quickly as the stamping process so that testing or inspection does not slow the overall process of making the part.
It is known to use stamping techniques to form a variety of parts having a head or a flange at an end thereof. For example, a substantially cylindrical or tubular part can be stamped to have a peripheral flange at one end. The stamping process may include a first formation process to form the flange in a gross, oversize configuration. A more precise clipping process is then used to ensure a reliable diameter by shearing away any excess material in the preformed flange. In a clipping process a peripheral portion of the stamped flange is removed as an annular ring so that the remaining portion on the part is of the desired diameter, and is positioned properly in the part.
A process to form a flange as described above can cause cracks to occur in the flange portion of the part. Cracks can cause the part to seal inadequately causing leaks, or to support inadequately and cause failure. Further, cracks can migrate over time, causing the part to fail prematurely. Accordingly, it is desirable to identify parts in which even small cracks have occurred before the part is put into use and fails. While complex, detailed metal analysis could be performed on each part, such testing is cost prohibitive for many parts that must be supplied inexpensively.
Accordingly, it is desirable to provide a device and process for testing stamped flange parts to reliably identify parts in which cracks have been created during the formation process.